Timepiece mechanisms are very liable to wear and some components, particularly those made of copper alloys, suffer from friction with an opposing component made of harder material, for example a steel alloy.
Thus, in a manual winding mechanism, a winding stem operated by the crown drives, with radial guiding, a winding pinion which meshes on a transmission wheel transmitting the rotation to a ratchet wheel on the barrel, directly or via a gear train. This winding pinion, generally made of steel, is axially guided and supported on an edge of the main plate of the movement, which is generally made of brass or similar. Wear rapidly occurs in this area of contact, and may require replacement of the main plate, which is expensive.
FR Patent Application No 880880A in the name of DEPERY describes an arrangement of balance staffs with pivots engaged in jewel holes formed by hollow screws fixed to the plates, with said screws axially receiving axial screws acting as endstones.
CH Patent Application No 188684A in the name of LA CHAMPAGNE describes a shock absorber bearing with a smooth, stepped, shock absorber, jewel hole.
CH Patent Application No 201680A in the name of FELSA describes a bushing housed in a bore in a plate and carrying a distinct fixed pivot projecting into said bore. A cylindrical shoulder integral with the arbour of a wheel set is slid onto the pivot, the arbour being fitted with limited endshake inside the recess formed by the bore and the pivot.
FR Patent Application No 1024708A in the name of ERISMAN describes a pivot with a hard metal coating, notably made of chromium.
WO Patent Application No 01/40881A1 in the name of KS22 SA-ECOFFET describes a watch crown screwed onto a sleeve assembled inside the watch case.
CH Patent Application No 497724A in the name of RECORD WATCH CO SA describes a winding mechanism wherein the axial position of the winding stem is determined by an elastically deformable fixed insert.
U.S. patent application Ser. No. 420,919A in the name of RAUSCHENBACH describes a winding mechanism provided with an insert.
CH Patent Application NO 131146A in the name of GISIGER UHRENFABRIKATIONS describes a winding mechanism including a sleeve.